Ability of Intraoperative Pathologic Analysis of Ductal Carcinoma In Situ to Guide Selective Use of Sentinel Lymph Node Surgery.

For patients with ductal carcinoma in situ (DCIS), sentinel lymph node (SLN) surgery is generally reserved for patients at high risk of being upstaged to invasive disease. The use of frozen section (FS) pathologic analysis of the primary tumor may allow for selective surgical nodal staging within one procedure. We sought to define the reliability of FS for detection of upstaging. Eight hundred and twenty-seven patients were identified with DCIS on core needle biopsy that underwent 834 operations at our institution between January 2004 and October 2014. We calculated the rate of upstage from DCIS to invasive cancer on both intraoperative FS and final pathology to determine the performance of FS. Upstage rate on final pathology was 118/834 (14.1%) 95 per cent confidence interval 11.8 to 16.7 per cent. FS identified 88/118 (74.6%) of the upstages. Specificity was 99.3 per cent (711/716). Overall accuracy was 95.8 per cent (799/834) and the positive predictive value was 96.0 per cent (711/741 patients). Mean size of invasive cancers identified on FS was 5.6 mm, versus 3.5 mm for those identified only on permanent section, P = 0.11. Intraoperative FS analysis of DCIS is useful for identification of upstage to invasive disease. This may facilitate a selective approach to SLN surgery that both decreases unnecessary SLN surgery and the need for a second operation.